Table 2.

Multivariate Weighted Odds Ratios (OR) and 95% Confidence Interval (95% CI) for Cognitive Tasks Based on Patterns of Sleep Duration (Unadjusted Model) and After Controlling for Potentially Confounding Variables (Adjusted Model) in the Final Logistic Regression Model^*

Risk factors	PPVT-R						Block Design
	Low (n=155† / n=136‡)			High (n=138† / n=123‡)			Low (n=225† / n=224‡)			High (n=191† / n=166‡)
	OR	95% CI	P	OR	95% CI	P	OR	95% CI	P	OR	95% CI	P
Unadjusted model§
Sleep duration patterns§
Short persistent duration	3.6	(1.9 – 6.7)	<0.001	0.4	(0.1 – 1.1)	0.08	0.9	(0.5 – 1.8)	0.84	0.9	(0.4 – 1.9)	0.75
Short increasing duration	2.2	(1.0 – 6.7)	0.04	0.7	(0.2 – 1.9)	0.45	2.5	(1.4 – 4.5)	0.003	0.7	(0.3 – 1.7)	0.48
10-h persistent duration	1.2	(0.8 – 1.7)	0.45	1.0	(0.7 – 1.4)	0.90	0.8	(0.6 – 1.1)	0.19	1.1	(0.8 – 1.5)	0.76
		n=915			n=915			n=1099			n=1099
Adjusted model‡
Sleep duration patterns§
Short persistent duration	3.1	(1.5 – 6.3)	0.002	0.4	(0.1 −1.3)	0.11	0.9	(0.5 – 1.8)	0.77	0.6	(0.3 – 1.5)	0.31
Short increasing duration	1.6	(0.7 – 3.9)	0.31	0.8	(0.3 – 2.5)	0.68	2.4	(1.3 – 4.4)	0.004	0.7	(0.3 – 1.8)	0.43
10-h persistent duration	1.2	(0.8 – 1.9)	0.42	1.0	(0.7 – 1.5)	0.92	0.8	(0.6 – 1.1)	0.20	0.9	(0.7 – 1.3)	0.74
		n=800			n=807			n=1,098			n=924

Data courtesy of the Quebec Institute of Statistics.

^*Data are expressed as weighted odds ratio (95% confidence interval).

^§The reference for sleep duration patterns in the logistic regression was children who slept 11-hour persistently.

^†Unadjusted odds ratio (95% CI) without controlling for potentially confounding factors.

^‡Adjusted odds ratio (95% CI) while controlling for sex of the child, maternal immigrant status, low parental education, young mother age, inadequate income, low birth weight, breastfeeding status, naptime at 29 months of age, hyperactivity-impulsivity and inattention at 17 months of age.